Bushing terminal guard



Nov. 18, 1941. E, TREANOR 2,263,319

BUSHING TERMINAL GUARD Filed Dec. 5, 1940 V Inventor: Edward D. Treanor,

His Attorney.

Patented Nov. 18, 1941 BUSHING TERMINAL GUARD Edward D. Treanor,Pittsileld, Mass., assignor to General Electric Company, a corporationof New York I Application December 3, 1940, Serial No. 368,344

2 Claims.

The present invention relates to an insulating terminal guard and whileit is not necessarily limited thereto, it is particularly suitable foruse with high voltage bushings of electrical apparatus.

Service outages frequently result from bushing arc-overs which have beeninitiated by foreign objects establishing a low resistance path from theapparatus terminals to ground. To cite a specific example, in the caseof distribution transformer installations it has been observed thatbirds are prone to alight on the transformer covers, and attracted bythe adjacent bright metal terminals parts, peek at them and thusinitiate an arc-over of the bushing. For preventing serviceinterruptions from causes as these, it is desirable to provide a simplemeans for covering or guarding the bushing terminals of electricalapparatus.

It is therefore an object of the present invention to provide a simple,inexpensive terminal guard for high voltage bushings and the likeapparatus.

It is a more specific object of the present invention to provide a newand improved terminal guard for bushings which may be readily attachedonto the upper end of the bushings.

In accordance with one form of the invention, the terminal guardcomprises a cup-shaped member of relatively resilient insulatingmaterial, such as of a molded resinous composition, which is provided onthe inner walls with a plurality of spaced and suitably notched fins forsnapping over the peripheral edge of the uppermost skirt of the bushinginsulator.

Further objects and advantages of the invention will appear from thefollowing description and the claims appended thereto taken inconnection with the accompanying drawing.

. In the drawing, Fig. 1 is a view of the upper portion of a transformerthe high voltage bushing of which is provided with a terminal guardconstructed in accordance with the present invention; Fig. 2 is anenlarged view illustrating the invention in greater detail; Fig. 3 is anenlarged fragmentary view further illustrating certain details; and Fig.4 is a fragmentary view illustrating a modification of the invention.

While in the drawing the invention is illustrated as it may be adaptedfor application to the high voltage bushing of a transformer, it will beobvious that the invention is not to be necessarily so limited. It willbecome apparent, as the description proceeds, that the guard of thepresent invention may be applicable for the protection of exposedterminals of insulator structures generally.

In the drawing the transformer I'll is provided with a cover Ii uponwhich is mounted a high voltage bushing i2 having a terminal stud I 3 atthe upper end thereof to which is connected the line lead 14. Thetransformer may also be provided with a lightning arrester l'5 which ismounted by a suitable bracket upon the side wall of the transformer tankand connected by means of the lead IE to the bushing terminal stud l3.

For the protection of the terminal parts at the upper end of the highvoltage bushing l2 against accidental contact by foreign objects, suchas a bird standing on the transformer cover, a guard i8 is attached tothe upper end of the bushing. The guard IB may be of any suitable shape,such as frusto-conical or cup-shaped as shown, having a tapered sidewall I9 and a fiat end wall 20. The end wall 20 is provided with anelongate slot 2i through which the line lead It may be extended and theside wall with a slot 22 for cooperatively straddling the lead wire itto the lightning arrester. Formed integrally with the inner side wall I!of the guard are a plurality of spaced, inwardly extending radial fins23 which are provided with notches 24 for cooperatively fitting aroundthe peripheral edge of the upper skirt 25 of the bushing insulator.

The guard l8 may be of any suitable insulating material, such as of amolded plastic composition. Preferably a composition of the resinoustype is selected so that the guard will have a certain inherentresiliency. As the guard is pressed downwardly upon the upper skirt ofthe insulator, the side walls I9 will flex somewhat to permit thelowermost beads of the notched fins 23 to slip over the skirt edgewhereby the guard will be held firmly in position.

In the modification illustrated in Fig. 4, the inwardly extending radialfins 28 of the guard are provided with a plurality of notches 29 whichare so tapered as regards the longitudinal axis of the guard as toaccommodate insulator skirts of varying diameters.

1. A guard for a bushing terminal comprising a cup-shaped member ofinsulating flexible material, said member having a flatend wall and atapered side wall, an opening in said end wall for 'a line lead.- anopening in saidside wallto accommodate another lead, a plurality of finsintegral with said side wall and extending inward- 1y from the innersurface thereof. and notches in said fins for cooperatively fittingaround the peripheral edge of an insulator skirt of said bushing.

2.-A guard for a bushing terminal comprising a cup-shaped member ofrelatively resilient insulating material, a plurality'ot ilns'extendinginwardly from the inner side walls of said meniher, said fins eachhaving a plurality oi notches ior cooperatively fitting around theperipheral edge oi an insulator skirt of said bushing, said notchesextending into a tapered portion of said tins so that a guard mayaccommodate insulator skirts of varying diameters.

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